1. Field of the Invention
This invention relates to the production of alkoxyalkanoic acids by the oxidation of the corresponding alcohols.
2. Description of the Relevant Art
Alkoxyalkanoic acids find use as anionic detergents. These acids being composed of only the elements C, H and O do not pose the environmental problems that other detergents containing heteroatoms such as N, S, and P pose. Commercially, the alkoxyalkanoic acids are prepared in a two-step process of first reacting an alkoxyalkanol with sodium and then reacting the resultant ethoxide with the sodium salt of chloroacetic acid. A one-step process avoiding the use of chloroacetic acid and providing a NaCl free product would be of significant commercial interest.
Japanese Pat. No. 50-96516 issued July 31, 1975, discloses a process for the preparation of carboxylic acid salts by the liquid phase dehydrogenation of alcohols with caustic alkali in the presence of precious metal catalysts, including palladium. This process uses a relatively high temperature, 100.degree.-270.degree. C. These high temperatures can degrade the ether linkages especially in the highly ethoxylated alcohols.
In U.S. Pat. No. 3,342,858, issued Sept. 19, 1967 discloses a lower temperature process using a platinum catalyst. This process uses an oxygen containing gas as the oxidant. This process presents all the problems attendant with two-phase operations such as gaseous diffusion limitations, additional equipment such as compressors needed to process the gas phase. A process operating substantially in the liquid phase overcomes many of these problems of gas-liquid phase reactions.